255 pump? fuel pressure

[Anthonytad1985]

Ok I had a stock fuel pump and it was getting old so I wanted to replace it with a 255.

So I got a 255 and put it in, checked the fuel pressure and took in for a ride. Well now it is running lean. I am thinking it is the wrong pump. I have the fuel pressure set at 55 with vac line off.

I have also been told with my set up 2.5 +20inj and a S60 15psi turbo I should have to run higher fuel pressure. This makes no sense that now with a 255 I would have to turn the pressure up thought.

Any ideas?

[87glhs232]

The vac/boost line is connected to your FPR right? Check your operating pressures while driving normal and under boost if you can. Make sure your not losing pressure and make sure your getting the 1/1 rise under boost. Also double check hose connections and make sure our not puking gas back there by the tank.

[Directconnection]

Did you get your 225 pump from Turbos Unleashed or FWD-P?

They sell legit Walbros. Ebay sells the chineese knock offs that also don't use the correct submergable fuel line.

TU and FWD-P also sells the 255 high pressure pump. There are supposedly 2 versions of the walbro 255.

[Anthonytad1985]

Did you get your 225 pump from Turbos Unleashed or FWD-P?

They sell legit Walbros. Ebay sells the chineese knock offs that also don't use the correct submergable fuel line.

TU and FWD-P also sells the 255 high pressure pump. There are supposedly 2 versions of the walbro 255.

I got the pump when i worked at my old shop it is a walbro.
I know that there are two different versions as far as high flow and high pressure. Not sure the one i got its been a while.
Would using one or the other cause this issue?

[turbovanman²]

If your running +20's on stock cal, you should be very rich. I would double check that you've got it installed properly. Tape up the fuel pressure guage so you can see it and go for a drive. As said, its 1:1 so at 10 psi of boost, the fuel pressure should be 65 psi. It could be a bad pump, bad fpr or a leak somewhere.

[Anthonytad1985]

I have a stage 3 set up for +20.
I was thinking of unhooking the vac line to the fpr and getting it hooked up to a hand pump so i can pump lets say 10-15psi while the car is running and see if the fuel pressure incresses that 10-15 psi. This way i can simulate a boost condition without the risk of a lean condition.

[moparzrule]

Stage 3 from FWD-P is meant for stock injectors.
When was the last time you changed you fuel filter?
The hand pump is a good idea.

[Anthonytad1985]

Stage 3 from FWD-P is meant for stock injectors.
When was the last time you changed you fuel filter?
The hand pump is a good idea.

Yeah cindy set up my stage 3 for +20. Fuel filter has been a while, but i dont think it would clog right when i changed the pump inless there was stuff in the tank i broke up. going to try and see what the hand pump shows tomorrow and will change the filter at the same time.

[moparzrule]

I had to change my filter within 2 weeks after I changed the pump. It stirs up the tank for sure.

[t3rse]

i dropped my tank and pressure washed it out...being careful not to bust the baffle...i agree though, probably filter...

[Directconnection]

I got the pump when i worked at my old shop it is a walbro.
I know that there are two different versions as far as high flow and high pressure. Not sure the one i got its been a while.
Would using one or the other cause this issue?

the phony pumps say walbro on them as well as the originals.

[turbovanman²]

Yeah cindy set up my stage 3 for +20. Fuel filter has been a while, but i dont think it would clog right when i changed the pump inless there was stuff in the tank i broke up. going to try and see what the hand pump shows tomorrow and will change the filter at the same time.

Yes, that works too, vacuum pumps work great for that.

I ALWAYS change the fuel filter when doing a pump, you'd be suprised at how many people never change the filters and take out there pump shortly after. Cheap insurance.

Try a volume test, you'll need a 1-2 litre container-tee off the feed line or use the fitting on the fuel rail, jump the coil + terminal-key off, then measure how much fuel you get in 30 secs, you should get at least 750 ml.

[mario03SRT]

The 255 HP I got from FM gave me fits with the same problem. Get into boost and it would lean out. Are you hearing any hissing?

Remove the diaphragm that in there for noise supression and install some fuel line in it's place. The diaphragm it not secured up top and it pushed on only.

Problem solved.

[Anthonytad1985]

The 255 HP I got from FM gave me fits with the same problem. Get into boost and it would lean out. Are you hearing any hissing?

Remove the diaphragm that in there for noise supression and install some fuel line in it's place. The diaphragm it not secured up top and it pushed on only.

Problem solved.

Is the "diaphragm" a check valve or like u said just a noise supression. Like you said it just slides no there and it was real loose, i was worried with that when i put it back in. I was going to remove it because of how losse it was but was worried it was some sort of check valve needed. I really think this along with the filter is my issue.

[mario03SRT]

Is the "diaphragm" a check valve or like u said just a noise supression. Like you said it just slides no there and it was real loose, i was worried with that when i put it back in. I was going to remove it because of how losse it was but was worried it was some sort of check valve needed. I really think this along with the filter is my issue.

It's only in there to suppress the pump whine.

I personally like to hear the pump prime up when turning on the key.

During driving you can't hear it with exhaust and stereo etc on.

Just take it out and bypass it with fuel grade hose. Badda Boom...Badda Bing!

I wish I knew that when I started my upgrade last summer.:o

[moparzrule]

What diaphram are we talking about here?

[mario03SRT]

What diaphram are we talking about here?

rulzer,

Inside the fp assy.

It goes on the backside of the outlet/inlet plate that goes on the outside of the fuel tank to the outlet of the actual pump. It's a 50 cent piece size diaphragm that resides in bewteen the plate and pump. It's supposed to be a resonator or attenuator of some sort for -----'s that can't stand the wwwrrrrrrrr when the ignition first comes on and throught operation.

[RoadWarrior222]

I ALWAYS change the fuel filter when doing a pump, you'd be suprised at how many people never change the filters and take out there pump shortly after. Cheap insurance.

If you were replacing your pump because it was sounding loud, it might have been straining against a clogged filter, might have only needed a filter change in the first place.

[Anthonytad1985]

If you were replacing your pump because it was sounding loud, it might have been straining against a clogged filter, might have only needed a filter change in the first place.

I was not having any issuse with my old pump. It just had 150,000 miles on it and i have alot of $$$ in my engine. Would not want to rebuild over a old pump. That and i wanted a bigger pump so if i wanted to run bigger injectors and higher boost i have the feul for it.

[shadow88]

You mentioned in the 1st post that it was running lean. I'd like to know what you measured the a/f ratio with, and how lean was it?

[Anthonytad1985]

You mentioned in the 1st post that it was running lean. I'd like to know what you measured the a/f ratio with, and how lean was it?

I measured it with a LC-1 and it was 13.1 WOT.
:confused2::confused2::confused2:
Well i tried the hand pump today 1.1 feul pressure. I taped the gauge to the windshield same. So i guess i have a flow issue :confused2:

[shadow88]

Nice to have a wideband.:thumb:

Will changing fuel pressure change a/f reading? I found I can change a/f reading by 1 point with 3 psi static.

[Anthonytad1985]

Nice to have a wideband.:thumb:

Will changing fuel pressure change a/f reading? I found I can change a/f reading by 1 point with 3 psi static.

I am just worried i have a leak at the diaphragm in the pump assembly, so i do not want to raise the pressure to try to make up for a leak. I guess i will gave to set time to pull the pump again and remove the diaphragm. :partywoot:
If i cant get that to work maybe i will just put my fuel cell in my trunk with a inline pump. :eyebrows:

[shadow88]

I see your concern. What I was getting at was possibly an injector problem. Maybe they're stock and maybe they're plugged a bit. Just a thought. Do you have any other known good +20's or known good stockers?

[Anthonytad1985]

I see your concern. What I was getting at was possibly an injector problem. Maybe they're stock and maybe they're plugged a bit. Just a thought. Do you have any other known good +20's or known good stockers?


No. If there where an injector problem though I would think it would have been there before I swapped the pump, innless I had a lot of crap in the tank I broke loose. Even then I would think the filter would be the issue.

But I did check the plugs to see if anything real bad was going on. The plugs seem to look good and read the same( a little white ). I check my plugs by WOT and shutting the engine off in WOT and pulling over.

The thing I just don’t understand is if I had a rich WOT before the swap, and that I have the same pressure now with the 1:1 boost pressure. the only thing it could be is a leak/clogged filter or a bad pump.

I just am so lazy for not changing the filter at the same time :o